In wireless communication receivers, the radio-frequency (RF) signal is amplified by one or more low noise amplifiers (LNA's) and down-converted to baseband. The resulting in-phase (I) and quadrature (Q) waveforms are further amplified and filtered before they are sampled with a pair of analog-to-digital converters (ADC's). The sampled waveforms are then processed so that the transmitted bit sequence is recovered. Distortion in the circuitry such as local-oscillator phase noise or gain/phase imbalances in the I and Q paths will affect the performance of the receiver.